[Cannabis: a harmless drug?].

Summarizing the literature of the past 25 years, we present a survey of the pharmacological effects of cannabis, which includes the pharmacological particularities of cannabis as a composition of substances with tetra-hydro-cannabinol as main component, the experimentally proved effects on animal cells, the experimentally and clinically proved damages to the central nervous system, respiratory tract, immune system and procreative system. The survey results in a warning: brain damage and dependency can be caused by cannabis and the resulting social consequences of an increasing consumption should not be underestimated.